当我使用文本框Text_Changed事件...选项卡索引不能正常工作

Question

设计页面：我正在使用母版页＆amp;更新面板＆amp;脚本管理器

   

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server">

</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            <table width="100%" cellpadding="8" cellspacing="8">
                <tr>
                    <td style="width: 11.11%;" align="right">
                        <asp:Label ID="Label10" runat="server" Text="Total Leave" CssClass="lab"></asp:Label>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotsick" runat="server" Width="100px" CssClass="textbox" AutoPostBack="true" 
                            ontextchanged="txttotsick_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotvacation" runat="server" Width="100px" AutoPostBack="true" 
                            CssClass="textbox" ontextchanged="txttotvacation_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotpaternity" runat="server" Width="100px" AutoPostBack="true" 
                            CssClass="textbox" ontextchanged="txttotpaternity_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotMaternity" runat="server" Width="100px" AutoPostBack="true"  
                            CssClass="textbox" ontextchanged="txttotMaternity_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotServiceIncentive" runat="server" Width="100px" AutoPostBack="true" 
                            CssClass="textbox" ontextchanged="txttotServiceIncentive_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotsoloparent" runat="server" Width="100px" AutoPostBack="true"
                            CssClass="textbox" ontextchanged="txttotsoloparent_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotBirthday" runat="server" Width="100px" AutoPostBack="true"
                            CssClass="textbox" ontextchanged="txttotBirthday_TextChanged"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txttotBreavment" runat="server" Width="100px" AutoPostBack="true"
                            CssClass="textbox" ontextchanged="txttotBreavment_TextChanged"></asp:TextBox>
                    </td>
                </tr>                    
                <tr>
                    <td style="width: 11.11%;" align="right">
                        <asp:Label ID="Label12" runat="server" Text="Balance Leave" CssClass="lab"></asp:Label>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalsick" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalvoacation" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalpartinity" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalmarternity" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalserviceincentive" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalsoloparent" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalbirthday" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                    <td style="width: 11.11%;" align="right">
                        <asp:TextBox ID="txtbalbreavement" runat="server" Width="100px" CssClass="textbox"></asp:TextBox>
                    </td>
                </tr>                   
        </ContentTemplate>
    </asp:UpdatePanel>
</asp:Content>

编码页面：我在Textbox TextChanged事件期间进行了一些计算......

protected void txttotsick_TextChanged(object sender, EventArgs e)
    {
        try
        {
            if (txttotsick.Text.Trim() != string.Empty)
            {
                txtbalsick.Text = (Convert.ToInt32(txttotsick.Text.Trim()) - Convert.ToInt32(txtconSick.Text.Trim())).ToString();
            }
            else
            {
                txtbalsick.Text = (0 - Convert.ToInt32(txtconSick.Text.Trim())).ToString();
            }
            txttotalbalanceday.Text = (Convert.ToInt32(txtbalsick.Text.Trim()) + Convert.ToInt32(txtbalvoacation.Text.Trim()) + Convert.ToInt32(txtbalpartinity.Text.Trim()) + Convert.ToInt32(txtbalmarternity.Text.Trim()) + Convert.ToInt32(txtbalserviceincentive.Text.Trim()) + Convert.ToInt32(txtbalsoloparent.Text.Trim()) + Convert.ToInt32(txtbalbirthday.Text.Trim()) + Convert.ToInt32(txtbalbreavement.Text.Trim())).ToString();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

在文本更改事件后，控件转到页面的第一个文本框...如何才能正确执行... 感谢...